Summary: qHTS of Patient Derived HCC Models to Identify Novel Probes/Therapeutic Agents Hepatocellular Carcinoma (HCC) accounts for > 90% of primary liver cancers and has an annual worldwide incidence of ~800,000 per year, and is the 2nd leading cause of cancer related death. HCC incidence is highest in South Asia and is ~2.4-fold more prevalent in males, and ~2-fold higher in non-Caucasians. HCC is associated with a range of environmental and infective etiologies including infection with hepatotropic viruses (HBV & HCV), non-alcoholic steatohepatitis (NASH), nonalcoholic fatty liver disease (NAFLD), alcohol and aflatoxin exposure, each of which contributes to liver pathogenesis. Liver cirrhosis is present in 80-90% of HCC patients and represents the single most important risk factor. HCC incidence is rising in developed countries due to a growing prevalence of metabolic syndrome and higher HCV infection rates. Obesity, insulin resistance and dyslipidemia, have emerged as a significant cause of NAFLD, cirrhosis, and HCC. NASH and NAFLD are global epidemics and evidence suggests that the risk of developing NASH related HCC is > for hepatitis-related cirrhosis. While only 5-20% of NAFLD patients progress to NASH in the USA, this means that 2-5% of the general population are at risk of developing HCC. Due to the lack of obvious symptoms during its initial stages, most HCC patients are diagnosed with advanced disease and survive <6 months. The median survival of patients receiving therapy is only ~6-20 months. 5-year survival rates for localized, regional and distant stages of HCC are 31.1%, 10.7% and 2.8% respectively. Liver transplantation, surgical resection, and ablation offer high response rates with potential for cures for early stage HCC. However, only 10%-23% of HCC patients are diagnosed early enough for such therapies. Trans-arterial chemoembolization or radioembolization are options for patents with preserved hepatic function and performance status. Systemic chemotherapy of advanced HCC with cytotoxic agents or drug combinations elicit response rates of only 10%-20%, and don?t prolong overall survival. Sorafenib, a molecularly targeted inhibitor of multiple tyrosine kinases is approved for HCC but improves overall survival by only ~3 months. Regorafenib, another multi-tyrosine kinase inhibitor (TKI) is approved for HCC patients with tumors progressing on sorafenib, also prolongs survival for only ~3 months. Despite the modest survival benefits of multi-TKI?s for HCC, several more are in clinical development. Immune checkpoint immunotherapies (Pembrolizumab or Nivolumab) targeting interactions between the anti-programmed cell death-1 protein (PD-1) receptor and its ligands (PD-L1 or PD-L2), or anti-cytotoxic T-lymphocyte antigen-4 (CTLA-4) (Tremelimumab), are also in clinical development for HCC. However, there remains an urgent unmet need for new and effective HCC therapies. The etiologic and genetic heterogeneity of HCC makes drug discovery/development challenging. We propose a phenotypic qHTS strategy to identify novel probes or therapeutic leads using unique patient derived HCC cell line models of HBV, HCV and NASH etiologies.